Mold and clamp for use in an automatic casting machine

ABSTRACT

An automatic casting machine having means for automatically and simultaneously introducing a casting material into a plurality of molds, filling means for automatically filling the molds to a predetermined level, mold carrying means adjustable to carry molds of different sizes, means for inverting the mold carrying means and the molds carried thereby to drain excess casting material therefrom, means for uprighting the mold carrying means and conveyor mechanism for transporting the mold carrying means from the filling means through a wall building station to the inverting means and thereafter through a draining station to the uprighting means and thereafter through a parts drying station to a mold unloading station and then to a mold conditioning station.

1451 se t. 17, 1am

[Init ttes Ratent 11 1 Meyer et a1.

[ MOLD AND cLAMP IFOR use 1N AN AUTOMATHC CASTING MACll-llilNE Primary Examiner-J. Spencer Overholser Assistant Examiner-David S. Safran 75 Inventors: Robert W. Me er, South E1 in; 1 Robert G. Swaiitson, Dundee both Agent Flrm prlmgley Dlthm'elll Og L f I11 Sandler & Stotland [73] Assignee: M1 and S Engineering, line, Dundee,

ABSTRACT [22] Filed: July 6, 1973 Appl. No.2 377,11 119 An automatic casting machine having means for auto matically and simultaneously introducing a casting Related US. Application Data [62] Division of Ser. No. 100,718, Dec. 22, 1970, Pat. No.

material into a plurality of molds, filling means for automatically filling the molds to a predetermined level, mold carrying means adjustable to carry molds of different sizes, means for inverting the mold carrying means and the molds carried thereby to drain excess casting material therefrom, means for uprighting the [52] US. 4125/4519, 249/164, 249/167 B29c 11/16 425/450 C; 249/139, 164,

[51] Int.

[58] Field of Search.........

249/l67 mold carrying means and conveyor mechanism for transporting the mold carrying means from the filling means through a wall building station to the inverting means and thereafter through a draining station to the References Cited UNITED STATES PATENTS uprighting means and thereafter through a parts dry- 249/l ing station to a mold unloading station and then to a 249/167 mold conditioning station. 425/450 C S N m NWT mA m mnDi mmP I Mm UON T A WP. UN 16 E R O F 1,837,452 LeMay..... 1,864,242 6/1932 3,768,952

8 Claims, 15 Drawing Figures 1,276,895 9/1968 Germany......................... 425/450 C m o 6 a 7, 0 i A 11 a 50 a s e w m T 1 E, w 6 o 8 6/ e. l t 7\ 6 EAIENTEBsm 1:914 3.836.314

sum 03 av n 360 FIG. 5 362 290 PMENIED 3E? 1 71974 SHEET 05 OF H FIG. 8

PAIENIEU SEP 1 7 I974 SHEET '09 HF 11 MOLD AND CLAMP FOR USE IN AN AUTOMATIC CASTING MACHINE This is a division of application Ser. No. 100,718, filed Dec. 22, 1970, now U.S. Pat. No. 3,801,255.

The present invention relates to an automatic casting machine and more specifically to a casting machine in which a plurality of molds are transported to a filling station in which the molds are automatically (1) filled to a predetermined level with a casting material, (2) transported to means for inverting the molds to drain excess casting material therefrom, (3) uprighted and (4) thereafter transported to a station in which the casting is removed from the mold.

An important object of the present invention is to provide an automatic casting system comprising a mold for receiving a casting material therein to form a cast ing, filling means for dispensing the casting material into the mold, means for draining excess casting material from the mold after the casting has been formed therein, and mold carrying means automatically for transporting the mold to the filling means and positioning the mold in the material-receiving position with respect to the filling means and for thereafter transporting the filled mold to the draining means.

Another object of the present invention is to provide, in an automatic casting system of the type set forth, means for inverting the mold after the casting has been formed therein thereby to drain excess casting material therefrom and means for uprighting the mold after the excess casting material has been drained therefrom.

Another object of the present invention is to provide, in an automatic casting system of the type set forth, means for forming a solid ceramic casting having a predetermined wall thickness.

Still another object of the present invention is to provide, in an automatic casting system of the type set forth, apparatus for accommodating molds of different sizes.

Still another object of the present invention is to pro vide an assembly of a multiple-part mold and mold clamp therefor for use in an automatic casting machine of the type set forth, the multiple-part mold having a casting-holding condition thereof and a castingreleasing condition thereof, at least one part of the mold being fixedly secured to the mold carrying means and another part of the mold being movable between a sealed position with respect to the fixed part of the mold to place the mold in the casting-holding condition thereof and an unsealed position with respect to the fixed part of the mold to place the mold in its castingreleasing condition thereof, the mold clamp having tensioning means and being shiftable between a closed position and an opened position thereof with respect to the other part of the mold, the mold clamp in the closed position thereof being tightly tensioned against the other part of the mold to seal the parts of the mold, the mold clamp in the opened position thereof being spaced from the other part of the mold, shifting of the mold clamp from the closed position thereof to the open position thereof operable to effect change of the mold from the casting-holding condition thereof to the casting-releasing condition thereof.

A further object of the present invention is to provide for use in a casting system of the type set forth an assembly of a multiple-part mold, a mold clamp and a mold carrier, the mold carrier having an L-shaped mold support connected to the conveyor means, one part of the mold being fixedly secured to the vertical leg of the L-shaped moldsupport and the other part of the mold being movable between a sealed position with respect to the one part of the mold to place the mold in a casting-holding condition thereof and an unsealed position with respect to the one part of the mold to place the mold in the casting-releasing condition thereof, and a mold clamp of the type hereinbefore set forth.

A further object of the present invention is to provide a filling mechanism for dispensing casting material into molds placed in a casting material-receiving position with respect to the filling mechanism, the filling mechanism comprising a frame, a filling head connected to the frame, motor means for moving the filling head with respect to the frame between a storage position and a dispensing position thereof, a nozzle carried by the head for directing casting material into a mold positioned in the casting material-receiving position thereof, sensing mechanism for sensing the level of casting material in the mold and for producing a signal when the level reaches a predetermined value, and control mechanism for holding flow of casting material through the nozzle in response to a signal from the sensing mechanism to fill each of the molds to a predetermined level and for actuating the motor means in response to the signal from the sensing mechanism to move the filling head from the dispensing position thereof to the storing position thereof to ready the filling heads for placement of another mold into the casting material-receiving position thereof.

A still further object of the present invention is to provide an inverting mechanism for use in an automatic casting system of the type set forth in which the inverting mechanism comprises a rotor assembly, means carried by the rotor assembly for maintaining the molds transported thereto by the conveyor means fixed with respect to the rotor assembly during rotation thereof, and motor means for rotating the rotor assembly and the molds carried thereby to invert: the molds and drain excess casting material therefrom.

Another object of the present invention is to provide for use in a casting system of the type set forth a combination of means for inverting a plurality of molds filled with a casting material to dump excess casting material therefrom and a conveyor system for transporting the molds in the upright position thereof to the inverting means and for transporting the molds in the inverted position thereof away from the inverting means, the conveyor system comprising four pairs of rails and a trolley assembly connecting each of the molds with the rails, the four pairs of rails forming a cruciform and vertical cross section, each of the trolley assemblies including a housing having four sets of wheels mounted thereon, each of the sets of wheels being spaced from the adjacent set of wheels and adapted to fit between the one pair of the four pairs of rails, the rotor mechanism of the inverting means including four pairs of rails forming a cruciform in vertical cross section and being complementary to the conveyor rails and being positioned near thereto to receive the trolley assembly and the molds carried thereby from the conveyor rail, and means for rotating the rotor mechanism to invert a mold carried thereby and to drain excess casting material from the molds.

A further object of the present invention is to provide apparatus for making hollow or solid ware of ceramic.

plastic, plaster and other materials where the raw material is in the liquid state.

A still further object of the present invention is to increase the mold life, improve the ware quality and to provide apparatus capable of handling a variety of mold sizes quickly and easily.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings in which:

FIG. 1 is a diagrammatic view of the automatic casting machine of the present invention particularly showing the spatial relationship of the various parts thereof;

FIG. 2 is a side elevational view of the inverting station and the uprighting station;

FIG. 3 is a front elevational view partly in section of a portion of the filling head of the filling station;

FIG. 4 is a front elevational view partly in section and partly broken away of a mold mounted on the mold carrying means and maintained thereon by one embodiment of the mold clamping means and showing the relationship between the mold carrying means and the conveyor system;

FIG. 5 is a rear elevational view of the filling station;

FIG. 6 is a perspective view of one embodiment of the mold clamping means and certain portions of the mold carrying means and the conveyor system;

FIG. 7 is a side elevational view partly broken away of the mold carrying means;

FIG. 8 is a side elevational view partly broken away of the filling station and particularly showing a mold in the liquid-receiving position thereof carried by a mold carrying'means and maintained thereon by the mold clamping means;

FIG. 9 is an end elevational view of the inverting and uprighting means and showing in phantom the various positions of the molds therein;

FIG. 10 is a side elevational view partly broken away of the inverting and uprighting means;

FIG. 11 is a front elevational view of a mold carried by the mold carrying means and maintained thereon by another embodiment of the mold clamping means;

FIG. 12 is a side elevational view of the apparatus shown in FIG. 11;

FIG. 13 is a side elevational view of a mold carried by the mold carrying means and maintained thereon by an embodiment of the mold clamping means and particularly showing the relationship thereof to the conveyor mechanism; and

FIGS. 14 and 15 are electrical schematic and diagrammatic views of the control circuit for the automatic casting machine of the present invention.

There is hereinafter disclosed and particularly shown in FIGS. 1 and 2 an automatic casting machine 50 in which a plurality of molds 55 each supported by a mold carrier 70 and maintained thereon by mold clamping means 110 or 150 are transported along a predetermined path on a conveyor system 205 driven by a drive unit 270. The molds 55 are first transported to afilling station 290 in which a liquid casting material or slip is introduced into the mold and thereafter the molds 55 are transported to a wall building station 440 where the casting is formed within the molds 55. From the wall building station 440 the molds are transported to a twisting station 445 in which the molds 55 are tilted a few degrees from the vertical and thereafter to an inverting station 450 wherein the molds 55 are inverted to dump the excess liquid casting material therefrom. When the molds 55 exit from the inverting station 450 they pass through another twisting station 570 and into a draining station 575. From the draining station 575 the molds 55 are thereafter transported to an upright ing station 580 wherein the molds 55 are returned to an upright position and therefrom they are transported to a parts drying station 585 and thereafter to a mold unloading station 590. In the mold unloading station 590 the mold clamping means 110 or 150 are moved from the closed position thereof to the opened position thereof to allow the finished casting to be removed from the molds 55. The molds 55 are then reassembled and the mold clamping means 110 or 150 are moved to the closed position thereof, the molds 55 thereby being in the materialreceiving condition thereof, the molds 55 thereafter being transported through a mold conditioning station 595 and then to the filling station 290.

With reference particularly to FIGS. 4 and 11 to 13, there is disclosed a typical mold 55 adapted for use with the automatic casting system hereof, the mold 55 being generally rectangular in cross section and having a top surface 56, a bottom surface 57 and upwardly inclined surfaces 58 interconnecting the bottom surface 57 with two opposed side surfaces 59, and also interconnecting an opposed rear surface 61 and a front surface 62 of the mold. The mold 55 is hollow and has an opening 63 in the top surface 56 thereof through which liquid casting material is poured to fill the mold 55. The molds 55 described herein are two-piece molds, each having a front half 65 and a rear half 66; however, molds of more than two parts can be used with the mold clamps and the automatic casting system described herein.

Each mold 55 has a material-receiving or castingholding condition in which the front half 65 and the rear half 66 are in sealed relationship to each other so as to retain therein liquid casting material in order to form a casting therein, and a casting-releasing condition in which the front half 65 and the rear half 66 are not in sealed relationship one to another and a casting within the mold 55 may be removed by separation of the two halves. The mold 55 may be made of any artrecognized material, plaster of paris being the preferred embodiment. The mold pieces preferably are provided with complementary dowels 67 and cavaties 68 (FIG. 13) to insure proper mating and alignment of the mold parts in the closed position.

Each mold 55 is maintained on an associated mold carrier '70, the mold carriers 70, as particularly shown in FIGS. 4, 6, 7 and 11 to 13, each including a flat platform 71 having the ends thereof formed into two parallel spacedapart end plates 72. A front angle plate 75 is positioned on the top of the platform 71 near the left hand end thereof as seen in FIGS. 6 and 7, the angle plate 75 including a vertical leg 76 and a horizontal leg 77, the horizontal leg 77 being in contact with the platform 71. The angle plate 75 is mounted on the platform 71 by means of spaced fasteners 78 (one only shown) which extend through apertures (not shown) in the horizontal leg 77 and through one of a series of apertures 73 in the platform 71, the apertures 73 being in the form of two spaced-apart parallel rows, thereby to permit adjustment of the angle plate 75 with respect to the lefthandmost edge of the platform 71. The vertical leg 76 of the front angle plate 75 has a cutout 79 in the center thereof.

The mold carriers 70 each include a vertically disposed lower back plate 85 having a plurality of horizontally spaced apertures 88 therein, the apertures 88 being provided for a purpose hereinafter to be explained. Two parallel spaced-apart vertical standards 98 are connected to the respective ends of the plate 85, such as by welding, and extend upwardly and away from the platform 71. Mounted on the upper ends of the vertical standards 90 is an upper back angle plate 95, the upper back angle plate 95 having a vertical leg 96 and a horizontal leg 97, the vertical leg 96 having therein a plurality of apertures 98 in vertical alignment with the apertures 88 in the lower plate 85.

There is further provided a plurality of mold support bars 108 suitably connected between the vertical leg 76 of the front angle plate 75 and the lower rear plate 85, thereby to form into one L-shaped unit the front angle plate 75, the lower rear plate 85, the standards 98 and the upper rear angle plate 95. The rear lower plate 85 is maintained in position relative to the platform 71 by a rod 102 which extends through one of a series of apertures 74 in each of the end plates 72, the rod 182 having special collars 103 outside of the end plates 72 and fixedly secured to the rod 102 by set screws 184 therein thereby to maintain the rod 102 in fixed relationship to the platform 71.

The mold carriers78 each are adjustable to carry thereon molds 55 of various sizes, the adjustment of the mold carriers 70 being provided by the series of apertures 74 in the end plates 72 through which extend the rod 182 in combination with the series of apertures 73 in the platform 71 through which extend the fasteners 78 for fixedly securing the front angle plate 75 to the platform 71. The combination of the front angle plate 75, the lower rear plate 85, the vertical standards 98, the upper rear angle plate 95 and the support bars 108 move as a unit to the left or to the right along the platform 71 as seen in FIG. 13, thereby to position molds 55 of different sizes in the center of the mold carrier 70.

With this construction, the unit defined by the front plate 75, the support bars 108, the rear plate 85, the standards 91) and the upper angle plate 95 also is rotatably mounted relative to the platform 71. Such movement can be effected by removal of the fasteners 78.

The rear half 66 of the mold 55 is fixedly connected to the associated mold carrier 78 by means of a plurality of fasteners 105, each fastener including an insert 106 of plastic or other suitable material imbedded within the rear surface 61 of the mold 55 and a threaded fastener 108 passing through an appropriate one of the apertures 88 in the lower rear plate 85 or one of the apertures 98 in the upper rear angle plate 95 and into the insert 106thereby fixedly to secure the rear half 66 of the mold 55 to the mold carrier 78.

The mold 55 is maintained in the casting-holding condition thereof by means of a mold clamp, there being two embodiments of mold clamps hereinafter described. As the molds 55 may be about 12 inches to about inches high having a base from about 7% inches to about 12 inches square, it is seen that more than one embodiment of the mold clamp preferably is provided in order fixedly to maintain both the smaller sized and the larger sized molds 55 in the castingholding condition thereof.

With particular reference to the mold clamp 118 shown in FIGS. 4, 6 and 13, there is disclosed a support bar 111 extending normal to the vertical standards of the associated mold carrier 70 and fixedly secured thereto such as by welding, the support bar 111 having two spaced-apart apertures 112 therein. The mold clamp 118 further includes two parallel spaced-apart rods or short arms 115, each of the: arms 115 being positioned to extend through one of the apertures 112 in the support bar 111. Each of the arms 115 has a groove 1 16 cut therethrough, each groove 116 extending from the forward end of the arm 115 rearwardly (to the right as seen in FIG. 13) to a point near the outer end of the arm 115. A collar 117 is fixedly mounted on the arm 115 as by set screw 119 and is positioned to the left of the support bar 111, that is toward the front of the mold carrier 78. A second collar 118 is fixedly secured to the arm 115 near the other end thereof, that is toward the right as seen in FIG. 13, the collar 118 cooperating with the support bar 111 to maintain a tensioning member in the form of a coil spring 121) in compression therebetween, the coil spring being positioned about the arm 115 and urging the arm 115 to the right as seen in FIG. 13. The mold clamp 110 further is provided with two parallel spaced-apart hinge members in the form of longer arms or hinge bars 125, the hinge bars 125 each being pivoted to the left-handmost end of the associated arm 115 by a hinge pin 126. The ends of the hinge bars 125 away from the hinge pins 126 are joined by a transverse connecting member in the form of a roll pin 128, the connecting member 128 having stub shafts 129 on each end thereof and extending through appropriate apertures in the adjacent bars 125, thereby rotatably to mount the connecting member 128 between the two bars 125.

Locking means in the form of a roller or lock bar assembly 138 fixedly is mounted to the connecting member 128 to rotate therewith, the roller assembly 130 including two parallel spaced-apart triangularly shaped plates or brackets 132 with the apex of the triangle being fixedly secured to the connecting member 128. An upper roller 134 is rotatably mounted between the roller brackets 132, the upper roller 134 having stub shafts 136 extending through the associated brackets 132. A lower roller rotatably is mounted between the roller brackets 132 in the other corner thereof, the lower roller 135 having stub shafts 137 on either end thereof extending through the associated roller brackets 132. Finally, the roller assembly 138 is provided with a handle 138 fixedly secured to the roller brackets 132 and being positioned parallel to the upper roller 134 and the lower roller 135 and approximately midway between the upper roller 134, the lower roller 135 and the connecting member 128.

As previously explained, the mold carrier 70 is adjustable to accommodate molds of different sizes. The mold clamp 110 associated with the mold carrier 70 is likewise adjustable by means of collars 117 and 118 to accommodate molds 55 ofv various sizes. For molds 55 of smaller depth than the one illustrated in FIG. 13, the collar 118 may be moved to the left so as to draw the roller assembly 130 to the right, this necessitating movement of the collar 117 to the left to provide room for the spring 128 to expand. The full-line illustration of the mold clamp 118 shows the clamp in the closed position thereof in which the front half 65 and the rear half 66 of the mold 55 are maintained in sealed relation one to the other such that the mold 55 is in the castingholding condition thereof. The phantom-line illustration of the mold clamp 110 shows the clamp in the opened position thereof in which the front half 65 and the rear half 66 of the mold 55 are maintained in an unrestricted relationship such that the mold 55 is in position to have the casting removed therefrom and is in the casting-releasing condition thereof. It is here noted that when the mold clamp 1 10 is in the opened position thereof, the front half 65 of the mold 55 easily may be tilted to the left or away from the rear half 66 of the mold 55 thereby to facilitate removal of a casting from the mold 55.

As best seen in FIG. 13, when the mold clamp 110 is in the locked position, the short arms 115, the hinge members or bars 125, and the connecting member 128 all lie in a common plane, with the rollers or lock bars 134 and 135 in a load-bearing position relative to the mold 55, the spring 120 serving to maintain adequate force on the aforesaid parts so as to maintain them in a stable condition. In the locked position, the lock bars or rollers 134 and 135 lie on opposite sides of the plane passing through the arms 115, the hinge members 125 and the connecting member 128, or in an overcenter position.

In order to open or unlock the clamp 110, it is necessary to move the lock bars or rollers 134 and 135 over center, or beyond the common plane. In order to open the clamp 110, it is necessary to overcome the force then being exerted by the spring in holding the parts in the stable condition. To accomplish this, the lock bars or rollers 134 and 135 may be moved vertically along the outside face 62 of the mold and, at the same time, a rotational force is applied to the handle 138 by the operator, by placing the palm of his hand on the connecting member 128 and the fingers on the handle 138 and then applying such rotational force. A typical torque requirement in order to accomplish the release action is on the order of 5 to 8 foot-pounds at the pivot point.

As rotation occurs, it will be appreciated that as either the roller 134 or 135 passes through the common plane it causes the hinge member 125 to move toward the left as illustrated in FIG. 13, thereby applying a greater compressive force on the spring 120. As soon as one or the other of the rollers 134 and 135 passes through the previously described common plane, the compression spring causes the arms 115 and hinge member 125 to snap back to the stable position thereof, wherein the collar 117 abuts the support bar 111.

It will be appreciated from the foregoing that operation of the mold clamp 110 is easily accomplished by the operator when it is desirable to separate the mold parts in order to remove a casting therefrom, while, at the same time, the mold clamp 110 provides more than adequate restraining force on the free mold part to hold the source in place during the casting operations.

In a typical example, the mold clamp 110 may have the approximate following dimensions: The short arm members 115 are about 6% inches long and about inch in diameter, with the slot 116 therein being approximately 5 )4 inches long; the hinge members 125 are approximately inches long (at the pivot points) for molds between about 7 inches and 9 inches in depth; while such members 125 may be about 13% inches long (at the pivot points) for molds that range from 10 /2 inches to 12 inches in depth. The roller bracket or plates 132 are about 4 inches long with the openings therein for the lock bars or rollers 134 and 135 being spaced approximately 2 inches on center, and the opening for receiving the handle 138 being approximately 1 15/16 inches from the vertical center line of the openings for the rollers. The connecting member 128 is about 12 3/16 inches long", the handle 138 is about 10 inches long; and the plates 132 are spaced about 5 1/16 inches apart. The rollers 134 and 135 are about 4 /8 inches long and are formed of a twoply rubber hosing having a /2 inch i.d. by "/8 inch ed; the roller shafts therefor being about 5 inches long. The

coil spring is about 2 inches in free length; it is about 1 3/32 inches in 0d. and the wire is about Va inch in diameter, there being three coils to the inch. An axial force of about 79 pounds is required to achieve 1 inch of deflection. The spring is preloaded so that when the clamp is in the unlocked condition, the spring is compressed about /2 inch, or about 40 pounds is being exerted thereby. To achieve locking or unlocking, the are subscribed by the rollers in passing over the center or common plane causes an additional deflection of about I /8 inch of the spring.

For molds 55 of larger dimension, more than one roller assembly is needed to provide adequate sealing between the two halves of the mold. To this end there is provided a second embodiment of a mold clamp, designated generally as 150, which embodiment is best illustrated in FIGS. 11 and 12.

There is disclosed in FIGS. 11 and 12 a mold clamp including two spaced-apart and parallel support bars 151 extending normal to the vertical standards 90 of the associated mold carrier 70, the support bars 151 being fixedly secured thereto such as by welding and each of the support bars 151 having two spaced-apart apertures (not shown) therein. The mold clamp 150 further includes for each of the support bars 151, two parallel spaced-apart rods or short arms 155, each of the arms 155 being positioned to extend through one of the apertures in each of the support bars 151. Each of the arms 155 has a groove 156 cut therethrough, each groove 156 extending from the forward end of the rod 155 rearwardly (to the right as seen in FIG. 12) to a point near the other end of the arm 155. A collar 157 is fixedly mounted on each of the arms 155 as by a set screw 159 and is positioned to the left of the respective support bar 151, that is toward the front of the mold carrier 70. A second collar 158 is fixedly secured to each of the arms 155 near the other end thereof, that is toward the right as seen in FIG. 12, each collar 158 cooperating with the associated support bar 151 to maintain a coil spring 160 in compression therebetween, each of the coil springs 160 being positioned about a respective one of the arms 155 and urging that arm 155 to the right as seen in FIG. 12.

The mold clamp 150 further is provided with two parallel spaced-apart hinge members in the form of longer arms or hinge bars for each of the support bars 151, each of the hinge bars 165 being pivoted to the left-hand end of an associated one of the arms 155 by appropriate hinge pins 166. To maintain each of the two hinge bars 165 in the same plane, the ends of the hinge bars 165 away from the hinge pins 166 are joined by a transverse connecting member or roll pin 168,

each of the connecting members 165 having stub shafts 169 on each end thereof and extending through the adjacent ends of the hinge bars 165, thereby rotatably to mount the connecting member 168 between the ends of the associated hinge bars 165.

A lock bar in the form of a roller assembly 1711 fixedly is mounted to each connecting member 168 to rotate therewith, the roller assembly 179 including two spaced-apart roller brackets 171, each of the roller brackets 171 being in the form of an elongated member having an aperture at one end thereof. One end of the roller bracket 171 is fixedly mounted to the connecting member 165 to rotate therewith, as hereinbefore explained, while the other end of the roller brackets 171 have a roller 175 rotatably mounted between the associated ones of the roller brackets 171, each of the rol lers 175 having stub shafts 176 on the ends thereof extending through the associated apertures in the roller brackets 171. Each roller assembly also is provided with a shaft 179 extending through the roller brackets 171 and being positioned substantially midway between the connecting member 168 and the roller 175, the shaft 179 acting as a gripping handle for movement of the roller assembly 170. There is further provided a stop bar 1511 mounted on each hinge bar 165, the upper hinge bar 165 having the stop bar 180 mounted on the upper side thereof and extending inwardly to contact the handle or shaft 179 when the roller assembly 170 has reached its counter-clockwisemost position with respect to the hinge bar 165. The lowermost hinge bar 165 has the stop bar 1811 mounted on the underside thereof where it extends inwardly to contact the handle 179 when the roller assembly 1711 is in the clockwisemost position with respect to the bar 165. It is noted that the stop bars 1511 contact the handles or shafts 179 to prevent further rotational movement of the roller assemblies 171] relative to the hinge bars 165.

The collars 157 and 155 and coil springs 160 operate in a manner similar to that of the respective collars 117 and 118 and coil springs 120 of the previously described mold clamp 1111. The full-line illustration of the mold clamp 150 shows the clamp 150 in the closed position thereof in which the front half 65 and the rear half 66 of the mold 55 are maintained in sealed relationship one to the other, such that the mold is in the casting-holding condition thereof. The phantom-line illustration of the mold clamp 150 shows the clamps in the opened positions thereof, in which the front half 65 and the rear half 66 of the mold 55 are maintained in an unrestricted relationship such that the casting can be removed therefrom. It is here noted that when the mold clamps 1511 are in the opened positions thereof, the front half 65 of the mold 55 easily may be tilted to the left or away from the rear half 66 of the mold 55 thereby to facilitate the removal of a casting from the mold 55.

The upper hinge bars 165 of the mold clamp 1511 may be moved to the opened position thereof by grasping the connecting member 166 in the palm and applying the fingers to the handle 179 and thereafter rotating the lock bar or roller 175 in the clockwise direction, causing it to pass over center relative to the hinge bar 165, arm 155 and connecting member 165, thereby to effect the same snap-action type movement heretofore described in connection with the clamp 110, this thus moves the upper hinge bars 165 from the full-line positions thereof to the phantom-like positions thereof. The lower hinge bars 165 may be moved to the opened position thereof by rotating the handle 179 in the counterclockwise direction, thereby to move the lower hinge bars 165 from the full-line position thereof to the pahntom-line position thereof. To move the mold clamp from the opened position thereof to the closed position thereof the procedure hereinbefore described is reversed, thereby to move the bar from the phantomline position thereof to the full-line position thereof. It will be understood from the foregoing that in this second embodiment of mold clamp the stop bar in effect acts as a second roller in that, once the roller 176 is moved through the center plane :and into the locked condition thereof, the stop bar prevents such roller from continuing on and rotating about to an unlocked condition.

In the second embodiment, the hinge members 165 are about 1 We inches long (at the pivot points) in order to accommodate the greater depth mold, while at the same time the clamps are vertically spaced on the mold at approximately 2% inches and 18% inches (on center) above the platform 71 of the mold carrier 70, whereas in the embodiment 110 the clamp was dis posed approximately 7% inches from the platform of the mold carrier. It is understood that the coil springs 121) and 169 provide the necessary resilience for the clamps 1111 and 150 during movement between the opened and closed positions thereof.

Irrespective of the size of mold 55 employed or whether the mold clamp 110 or the mold clamp 150 is used, the associated mold carriers 70 each have two spaced-apart parallel angle irons fixedly connected to the bottom of the platform 71. Gne of the angle irons 196 is secured along the edge of the platform 71 away from the vertical standards 90, that is the left-handmost edge of the platform 71 (as seen in FIGS. 6 and 13) and the other angle iron 190 is fixedly secured near the right-handmost edge of the platform 71, that is below the vertical standards91). Each of the angle irons 190 includes a vertical plate 191 extending downwardly perpendicularly from the platform 71 and a horizontal plate 192 extending parallel and fixed to the bottom of the platform 71. Each of the angle irons 190 has rotatably mounted thereto two whee1s 195, each of the wheels 195 being mounted to the vertical plate 191 near the opposite ends thereof by means of a threaded fastener 196 extending through an. associated aperture in the vertical plate 191 and through the associated wheel 195. Each of the wheels 195 is maintained about the associated fastener 196 by a washer 198 mounted between the associated vertical plate 191 and the wheel 195 and a nut 197 on the threaded fastener 196 thereby to allow the wheel 195 freely to rotate about the threaded fastener 196. Each of the mold carriers 70 has a center bar 2611 (FIG. 13) extending perpendicularly downwardly from the bottom of the platform 71 and positioned midway between the associated wheels 195, the center bar 2111) being for a purpose hereinafter explained.

The conveyor system 2115 hereinafter described is sold by the AMERICAN MONORAIL Division of Fischer Industries under the name of CHAINLESS Conveyors, 600 Series, such as illustrated in their brochure S & P Manual AM I 00. The conveyor system 205 is best illustrated in FIGS. 41, 6 and 13. The conveyor system 2115 includes two parallel spaced-apart outer tracks 210, each in the form of an angle plate having a vertical leg 211 and a horizontal leg 212. Each of the outer tracks 210 is fixedly secured by suitable fasteners 213 to the longitudinally extending plate 216 of a plurality of spaced-apart struts 215, the struts 215 being spaced apart along the conveyor system 205 to support the same and each including a longitudinally extending plate 216 and a transversely extending plate 217. As may be seen by reference to FIG. 1, the conveyor system 205 forms a closed path generally oval in shape with the struts 215 being spaced apart therealong to provide sufficient support therefor. Mounted to each of the struts 215 is a support bracket 220, the support brackets 220 being generally U-shaped and mounted to the transverse plates 217 of the associated strut 215 by suitable fasteners 221. Each of the support brackets 220 has two spaced-apart upper lugs 225 positioned between the ends of the transversely extending plates 217 of the associated strut 215, the upper lugs 225 extending parallel to the direction of the travel of the molds 55. Each of the support brackets 220 has two spacedapart lower lugs 226 positioned between the ends of the transversely extending plates 217 of the associated strut 215, the lower lugs 226 extending parallel to the direction of travel of the molds 55.

Two spaced-apart parallel inner upper tracks 230, each in the form of an L-shaped plate having a vertical leg 231 and a horizontal leg 232 are fastened to the associated upper lug 225 of the support brackets 220 by means of fasteners 234, the tracks 230 extending parallel to the outer tracks 210 for the entire length of the conveyor 205. Two parallel spaced-apart inner lower tracks 235, each in the form of an L-shaped plate having a vertical leg 236 and a horizontal leg 237, are fastened to the associated lower lug 226 of the support brackets 220 by meansof fasteners 239, the tracks 235 extending parallel to the outer tracks 210 for the entire length of the conveyor 205. A clevis 245 having two spaced-apart triangular side plates 246 interconnected by a bight 247 is secured to the center bar 200 of each mold carrier 70 by a fastener 249 extending through aligned apertures (not shown) in the triangular side plates 246 and the center bar 200, the clevis 245 forming a part of the connection between each of the mold carriers 70 and the conveyor system 205.

The conveyor system 205 is provided with a plurality of trolley assemblies 255, there being one trolley assembly 255 for each of the plurality of mold carriers 70. Each of the trolley assemblies 255 includes a hollow cylindrical body 257 (FIG. 4) having mounted thereon a plurality of wheels as follows: four wheels 260 are mounted on the cylindrical body 257, two on each opposite side thereof, the wheels 260 being retained between the horizontal legs 232 of the inner upper tracks 230 and the horizontal legs 237 of the inner lower tracks 235; two wheels 261 are mounted on the upper surface of the cylindrical body 257, so that they are retained between the vertical legs 231 of the inner upper tracks 230; and two wheels 262 are mounted on the lower surface of the cylindrical body 257, so that they are retained between the vertical legs 236 of the inner lower tracks 235; the wheels 261 and 262 are mounted on the cylindrical body 257 by means of threaded fasteners 265 extending through the bight 247 of the associated clevis 245, through the wheel 261, through the cylindrical body 257, and through the wheel 262; the wheels 260 are mounted on the cylindrical body 257 by means of fasteners 266 extending through one of the wheels 260, the body 257 and another wheel 260. Each of the trolley assemblies 255 is connected one to another by connecting rods 278, each connecting rod 278 terminating in a ball (not shown) housed in a ball socket formed in each end of the associated cylindrical body 257.

As particularly seen in FIG. 1, there is also provided a drive mechanism 270 for the conveyor 205, the drive mechanism 270 including a motor 271 having a drive shaft 272 extending therefrom with a drive wheel 273 mounted thereon. A belt 274 interconnects the drive wheel 273 mounted thereon. A belt 274 interconnects the drive wheel 273 with a driven wheel 275 mounted to a gear reducer 276, the gear reducer 276 having an output shaft 277 extending therefrom in driving relationship with the trolley assemblies 255 of the conveyor 205, thereby to drive the trolleys 255 in a counterclockwise direction, as seen in FIG. 1 along the closed path hereinbefore described.

As seen from the drawings, the conveyor system 205 provides support for the plurality of mold carriers 70, each of the mold carriers riding with the wheels thereof on the horizontal leg 212 of the outer tracks 210. The conveyor system 205 provides transportation of the mold carrier 70 along the closed path hereinbefore described by means of the drive mechanism 270 which propells the individual trolley assemblies 255 along the closed path, the mold carriers 70 being connected to the trolley assemblies 255 by means of the center bar 200 and clevis 245. The construction of the upper inner tracks 230 and the lower inner tracks 235 in combination with the position of the wheels 260, 261 and 262 positioned between the associated tracks 230 and 235 maintain the mold carrier 70 in contact with the upper tracks 210 regardless of the angle of tilt of the conveyor system 205, the conveyor system 205 being constructed to maintain the mold carrier 70 in contact therewith during rotation of the mold carrier 70 for a full 360 revolution.

As best seen in FIGS. 1, 5 and 8, the molds 55 each of which is carried by a mold carrier 70 are transported by the conveyor system 205 to the filling station 290 where each of the molds 55 is filled to a predetermined level with a liquid casting material which hardens in the molds 55 to form a casting therein. The liquid casting material or slip may be any art-recognized medium from a clay to a plastic resin. The filling station 290 includes a frame 291 having a base plate 292 formed at the rear thereof into an angle member 293. Two parallel spaced-apart upstanding side plates 295 and 296 are interconnected by a front plate 297. The construction of the side plates 295 and 296 with the front plate 297 is stabilized by an upper support shelf 298 suitably secured to the side plates 295 and 206 by fasteners 299 and a lower support shelf 300 suitably connected to the side plates 295 and 296 by fasteners 301. Two stops 302 are positioned opposite each other one on each of the side plates 295 and 296, the stops 302 being for a purpose hereinafter explained. There is further provided an angle iron 305 on the outside of the front plate 297, the angle iron 305 being horizontally disposed and generally parallel to the base plate 292. The angle iron 305 forms a support for two spaced-apart generally parallel support bars 306, the support bars 306 being connected at one end to the angle iron 305 and at the other end to a support bar 307, the support bar 307 being positioned at right angles to the support bar 366 interconnecting the support bar 306 with the base plate 292. The angle iron 305, support bar 386 and support bar 307 form a base for a drip pan 388 which rests on the frame or base formed thereby and against the front plate 297 of the frame 291, the drip pan 388 being prevented from sliding off of the support bar 306 by a retaining plate 369.

The filling station 290 further includes two main lift rods 315, the lift rods 315 are spaced apart and parallel, the rods extending vertically through upper lift rod bearings 316 maintained in the upper support shelf 298 and through lower lift rod bearings 317 maintained in the lower support shelf 308. Each of the main lift rods 315 has at the lower end thereof a lift rod end cap 318 and a fastener 319 connecting the end cap to the lift rod. Further, th lift rods 315 have a horizontally extending coupling plate 320 fixedly connected thereto by means of fasteners 321. The main lift rods 315 are vertically movable through the bearings 316 and 317 as shown by the differences in the solid-line position and the phantom-line position of the lift rods 315 in FIG. 5, the coupling plate 326 being fixedly connected to the lift rods 315 is also vertically movable as shown by the solid line position and the phantom line position thereof in the drawings.

Vertical movement of the main lift rods 315 and hence the coupling plate 320 is provided by a motor 325 having a brake 326 connecting thereto and leading to a gear reducer 327. The gear reducer 327 is mounted on a mounting plate 328 by a plurality of nuts and bolts 329 firmly connecting the gear reducer 327 and hence the motor 325 and brake 326 to the base plate 292 of the frame 291. An output shaft 330 from the gear reducer 327 is connected to a sprocket 332. A chain 333 interconnects the sprocket 332 with a sprocket 335 mounted to collar 336 and to drive shaft 340. The drive shaft 340 is joumaled in bearings 341 suitably mounted on the respective side plates 295 and 296. The drive shaft supports two spaced-apart sprockets 342, each of the sprockets 342 being fixedly connected to the drive shaft 340 by set screws 343 to rotate with the drive shaft 348.

There is further provided an idler shaft 345 vertically spaced apart from the drive shaft 348 and parallel thereto, the idler shaft 345 being suitably joumaled in idler shaft bearings 346 mounted on the respective side plates 295 and 296 of the frame 291. The idler shaft 345 supports two spaced-apart sprockets 347, each being fixedly mounted on the idler shaft by set screws 348, each of the sprockets 347 being vertical alignment with an associated one of the sprockets 342. Each of the associated sprockets 342 and 347 is interconnected by a chain 356, each of the two chains 351) having tensioning screws 351 and nuts 352 connecting the chains 358 with the coupling plate 326 and maintaining sufficient tension in the chains 358 to maintain engagement of the chain links with the teeth of the individual sprockets 342 and 347. Therefore, it is seen that rotation of the drive shaft 340 by activation of the motor 325 results in movement of the chain 350 and hence vertical movement of the coupling plate 326 and the main lift rods 315 fixedly connected thereto.

Fixedly connected to the main lift rods 315 and vertically movable therewith is a filling head 368 movable between a dispensing position and a storage position, the filling head 360 including two spaced-apart parallel side plates 361 interconnected by a rearwardly diagonally extending top plate 362 and. a forwardly diagonally extending top plate 363 and a vertically extending rear plate 364. A front cover 365 extends beyond the side plates 361 and includes a top plate 366 interconnecting two spaced-apart parallel end plates 367. The front cover 365 further includes a front plate 368 and associated end plates 367 with the side plates 361. The front cover 365 is hingedly connected to the forward top plate 363 as at hinge 371 to facilitate easy access to the filling mechanism housed within the front cover 365, the aforementioned top 366, end plates 367, front and rear plates 368 and 369 being assembled by suitable fasteners 372. A lower bracket 375 fixedly secures each of the main lift rods 315 to the filling head 360 by means of fasteners 376 and an upper bracket (not shown) fixedly secures each of the lift rods 315 to the filling head 360 by means of fasteners 378.

There is further provided a plurality of fluid nozzles 388 housed within the front cover 365 for introducing the liquid casting material or slip into the molds 55 when the molds are positioned in the liquid-receiving position thereof, as will more fully be explained hereinafter. While there is shown in the particular embodiment disclosed herein three spaced-apart fluid nozzles 386, it will be appreciated that less than or more than three of the fluid nozzles 388 may be housed within the filling head 360. The molds 55 are in the liquidreceiving position thereof when the opening 63 therein is in registry with one of the fluid nozzles 380, the associated mold carrier 70 being adjusted for each different sized mold 55 carried thereby so as to position the center of the opening 63 of the associated mold 55 in vertical alignment with the fluid nozzlle 380. Each of the fluid nozzles 380, as particularly seen in FIG. 3, has connected thereto a valve 381 and is mounted to the filling head 360 by means of a mounting assembly 382, operation of the valve 381 permitting liquid casting material to flow through the nozzle 380 or preventing liquid casting material from flowing through the nozzle 386.

There is further provided a light source 385 and a photoelectric cell 386 for each of the nozzles 380, the light source 385 and photoelectric cell 386 being angularly mounted with respect to the associated nozzle 380 and adapted to actuate (in a manner hereinafter explained) the valve 381 when the liquid casting material or slip introduced into the associated mold 55 reaches a predetermined level to halt introduction of the liquid material thereinto. There is further provided a water nozzle 387 behind each of the fluid nozzles 380, the water nozzle being positioned in registry with the opening 63 in the associated mold 55 and having control mechanism (not shown) so as to introduce a layer of water on top of the liquid casting material or slip after the introduction thereof into the associated mold 55, for a purpose hereinafter explained. The filling head 360 is provided with two stop plungers 390, there being a stop plunger 39]) mounted adjacent to each of the end plates 367. Each of the stop plungers 390 includes a slidable shaft 391 having an end cap 392 thereon and a coil spring 393 positioned thereabout to bias the stop plunger 398 to its fully extended position. When the filling head 366 is lowered, as hereinafter explained, the stop plunger 390 contacts the top surface 56 of an associated one of the molds 55 and compresses the plunger 390 until the slidable shaft 391 actuates a switch 395 which causes the motor 325 to stop and the brake 327 to engage.

The filling head 360 further is provided with a drip pan 400 movable between a collecting position, shown in full-line in FIG. 8, and a storage position, shown in phantom-line in FIG. 8. The drip pan 400 includes a front wall 401 and a back wall 402 spaced apart and parallel thereto, the front wall 401 and back wall 402 being interconnected by two parallel side walls 403 and a bottom wall 404. The drip pan 400 is further provided with two pan support brackets 405 each of which is positioned near an associated side wall 403 of the drip pan. A tray pivot arm 407 is pivotally mounted intermediate the ends thereof on each of the side plates 361 of the filling head 360 by a stub shaft 408. The lower end of each of the tray pivot arms 407 is pivotally mounted to the rear, that is the left-hand endmost portion as seen in FIG. 8, of the pan support bracket 405 by a pin 409. A coil spring 415 has one end thereof fixedly mounted on a bar 416 extending between the side plates 361 and suitably mounted thereto and has the other end thereof secured to a bar 417 interconnecting the two tray pivot arms 407, the coil springs 415 tending to bias the drip pan 400 into the storage position thereof. There is further provided two idler arms 420, each of the idler arms 420 having one end thereof pivotally connected to an associated side plate 361 by an idler arm stud 421 and having the other end thereof pivotally connected to the front end, that is the right-handmost end as seen in FIG. 8, of the pan support bracket 405 by a pin 422. There is further provided two chains 425 each of which is mounted by a pin 426 to the other end of each of the tray pivot arms 407 and extends over an idler sprocket 427 rotatably mounted to the associated side plate 361 by a stub shaft 428 and then downwardly to a draw bar 430 pivotally connected to the outermost ends of the coupling plate 320 by a pin 431.

It is seen therefore that when the motor 325 is opera tive to drive the chain 333 in one direction and hence the drive shaft 340, the coupling plate 320 is moved upwardly thereby also to move therewith the main lift rods 315. When the main lift rods 315 are moved to their uppermost position, the filling head 360 moves therewith to the storage position thereof and as the draw bars 430 move upwardly and contact the stops 302, further movement of the draw bars 430 is prevented thereby and the effective length of the chains 425 is changed, thereby to pivot the tray pivot arms 407 about the stub shafts 408 against the pull of the springs 415 to move the drip pan 400 from the storage position thereof to the collecting position thereof in which the drip pan 400 is in position to catch any of the liquid material or slip which may drip from the nozzles 380. When the molds 55 are moved into the liquidreceiving position thereof by the conveyor system 205 and the mold carriers 70, the motor 325 is activated to rotate the drive shaft 340 in the opposite direction thereby to lower the main lift rods 315 and hence the movable plate 320 are lowered, the draw bars 430 disengage from the stops 302 and are free to rotate about the pins 431 to their full-line position as shown in FIG. 8, thereby to allow the springs 415 to draw the drip pan 400 rearwardly into its storage position and away from the nozzles 3 80. The filling head 360 proceeds downwardly in response to operation of the motor 325 until the stop plungers 390 contact the top surface 56 of a mold 55 thereby actuating the switches 395 to stop the motor and apply the brake to prevent further downward movement of the filling head 360. When the filling head 360 has reached its lowestmost position, as

' seen in the phantom-line position of FIG. 8, the filling head 360 is in the dispensing position thereof and the valves 381 are actuated to dispense liquid casting material or slip through the nozzles 380 into the associated molds 55 until the liquid level in the molds is such to cause the light source 385 and photoelectric cells 386 to again actuate the valves 381 to halt the flow of the liquid casting material through the nozzles 380, the photoelectric cell being set to receive reflected light of sufficient intensity when the liquid level is about inch from the top of the mold. Thereafter, water is introduced into the associated molds 55 through the water nozzles 387, the water flowing thereinto for a predetermined time after which a valve (not shown) is actuated to halt the same.

After the molds 55 are filled to the predetermined level with the liquid casting material or the slip and thereafter have a predetermined amount of water deposited on top of the liquid casting material and the filling head 360 has been returned to the storage position thereof, the filling molds 55 are moved by the conveyor system 205 away from the filling station 290 into the wall building station 440. The wall building station 440 is an enclosed area about a section of the conveyor system 205 in which an inlet air duct 441 and an outlet air duct 442 are provided in order to circulate air at a predetermined temperature and humidity more rapidly to effect formation of a casting within each of the molds 55 by accelerating the absorbtion of water from the liquid casting material through the mold 55 and evaporating the water from the mold walls into the controlled atmosphere of the wall building station 440. The water introduced on top of the liquid casting material is sufficient to prevent formation of a solid coating across the opening 63 in the top surface 56 of the molds 55 during transportation through the wall building station 440, thereby to permit the excess liquid material to be drained or dumped from each of the molds 55, all as hereinafter explained.

As each successive series of three molds 55. is filled in the filling station 290, the conveyor system 205 moves the molds 55 along the closed path in a counterclockwise direction as viewed in FIG. 1. The desired wall thickness of the casting formed in each of the molds 55 is determined by the temperature and humidity of the air circulated within the wall building station 440, the length of time the molds 55 reside therein and the length of time before the excess material is dumped therefrom. Upon leaving the wall building station 440, the molds 55 are transported by the conveyor system 205 through a twisting station 445 in which the conveyor system 205 is tilted at a slight angle of about 10, so as to reposition the vertical axis of the molds 55 with respect to the true vertical. After the molds 55 pass through the twisting station 445, they enter the inverting station 450.

The inverting station 450 includes a pair of vertical supports 451 spaced apart and extending substantially vertically upwards and interconnected at the front and rear ends thereof by a track holding support 452. The bottom of the vertical supports 451 are joined by a front base angle iron 453 and a rear base angle iron 454 and two side frames 455 and 456. A top frame 457 in- 

1. A mold and clamp combination comprising a first mold part, a second mold part movable between a sealed position relative to said first mold part to place said mold in a casting materialreceiving condition and an unsealed position relative to said second mold part whereby a hardened casting may be removed from said mold; a mold clamp including first fixed means secured to said first mold part, locking means movable between locked and unlocked positions relative to said second mold part for retaining said second mold part in the sealed position relative to said first mold part, and tensioning means for holding said locking means in the locked position thereof; said locking means comprising a pair of arm portions slidably mounted on said first fixed means on opposite sides of said first mold part, a pair of hinge members each pivotally connected at one end to the respective ends of said first arm portions, a connecting member rotatably secured to the respective outer ends of said hinge members, and a lock bar secured to said connecting member for rotation therewith relative to said hinge members, said lock bar being movable to a load-bearing position relative to said second mold part to hold said second mold part in the sealed condition relative to said first mold part, said first arm portions and said hinge members and said connecting member being arranged so that they lie in a common plane when said lock bar is in the loadbearing position with said tensioning means being operable to retain said connecting member and said arm portions and said hinge members in a stable position, rotation of said lock bar to a disengaged position relative to said second mold part requiring exertion of a greater force on said tensioning means before said hinge members and said connecting member can be rotated relative to said first arm portions, said greater force being obtained by rotation of said lock bar and said connecting member beyond the stable position thereof to effect a snap movement of saiD slidable first arm portions relative to said tensioning means.
 2. The combination set forth in claim 1, wherein said locking means includes a pair of lock bars secured to said connecting member in fixed relation to each other, said lock bars being arranged such that when said lock bars are in the load-bearing position, they lie on opposite sides of the plane passing through said connecting member and said first arm portions and said hinge members.
 3. The combination set forth in claim 1, and further including plate means interconnecting said pair of lock bars and said connecting member and further including a handle carried by said plate means for facilitating rotation of said lock bars and said connecting member between the locked and unlocked portions thereof.
 4. The combination set forth in claim 1, wherein at least one of said hinge members includes a stop member thereon which prevents movement of said lock bar into the common plane of said pair of arms and said hinge members and said connecting member when said lock bar is in the load-bearing position.
 5. The combination set forth in claim 1, wherein said tensioning means comprises at least one compression spring disposed about one end of one of said first pair of arms.
 6. The combination set forth in claim 1, and further comprising a pair of said mold clamps fixedly secured to said first mold part and in spaced relations thereon.
 7. The combination set forth in claim 1, wherein said first mold part is fixedly secured to a frame and said first fixed means comprises part of said frame, said frame including a base portion adapted to support the bottom surface of the associated mold.
 8. The combination set forth in claim 7, wherein the fixed portion of said frame and said fixed mold part are adjustable relative to said base portion of said frame whereby said mold carrying means may accommodate molds of various sizes. 